In the United States, students in elementary and high school spend, on average, 1400 hours in school buildings every year [1
] learning, playing, eating, and interacting with one another. When considering that young children, teenagers, and adults all congregate in school buildings for these many hours a year, there is growing concern on the quality of the environment in which they are exposed. School facilities exist to provide students a productive learning experience, but poor facility conditions have a tremendous impact on students’ health and performance. Decaying environmental conditions such as peeling paint, crumbling plaster, nonfunctioning toilets, poor lighting, inadequate ventilation, and inoperative heating and cooling systems can affect the learning as well as the health and morale of staff and students.
Many of the schools that currently exist were built before 1984, [2
] and most of them have systems and assemblies in deteriorating condition [2
]. Air circulation, which is important for Indoor Air Quality (IAQ) and occupant health, may be affected by these old and deteriorating systems. IAQ can be affected by gases (including carbon monoxide and volatile organic compounds), particulates, microbial contaminants (mold, bacteria, etc.), or any mass or energy stressor that can induce adverse health conditions. Hence, good ventilation is vital for schools because compared to adults, children breathe a greater volume of air in proportion to their body weight [6
]. In addition, schools have much less floor space per person than found in most office buildings [7
Research within the last 10 years has shown that approximately 8.5% of children have asthma [8
], which has led to over 13 million missed school days [8
]. Furthermore, asthma and other respiratory illnesses have been linked to the indoor environment and indoor air quality (IAQ). The presence of particulates such as NO2
, and PM2.5
, or excessive moisture in the indoor environment from inadequate ventilation has triggered asthma attacks in children [11
]. Ventilation systems allow for the removal and dilution of breathing air contaminants such as CO2
and CO that build up within enclosed spaces over time. However, with old building systems or malfunctioning systems, the efficiency and regulation of indoor air quality is compromised. Moreover, research studies such as [14
] have shown a correlation between low indoor air quality, and reduced student attendance. In a 2004 multiple-building study of 436 classrooms in 22 elementary schools in Washington and Idaho, Shendell et al. of Lawrence Berkeley National Laboratory (LBNL)determined that a 1000 ppm increase in net (indoor minus outdoor) classroom CO2
concentration is associated with an average 0.7% decrease in annual average daily student attendance, indicating that attendance may be improved by an increased ventilation rate and lower CO2
Beyond air quality, achieving optimal indoor environmental quality (IEQ) in schools requires full assessment of lighting, acoustics, thermal, and spatial conditions. One of the most critical physical characteristics of the classroom is lighting. Depending on the building orientation, site characteristics, local climate, and latitude, the amount of daylight that schools receive can be drastically different. The level of daylight in a classroom is vital as there can be significant visual problems if there is too little or too much daylight. Proper daylighting in classrooms provides multiple benefits including a reduction in the building’s energy consumption and heat gain, improved academic performance, and improved sleep and cognitive functions. Several studies identify strong correlations between daylighting access in classrooms and improvements in student test scores. A 1999 Heschong Mahone Group research study of multiple school districts in Seattle, Washington, and Fort Collins, Colorado showed that students “in classrooms with the most day lighting were found to have 7% to 18% higher scores than those with the least” [16
In addition, an optimal acoustical environment will support a good listening space for students and a good acoustic venue for teachers. Proper acoustical support is crucial to young children because their auditory and language faculties are still developing. According to the Acoustical Society of America, “developmental status, linguistic and cognitive proficiency, temporary hearing impairments, and early receptive and expressive language disorders” are all factors that affect the greater susceptibility of young children to background noise and reverberation. [18
]. A good acoustical environment should enhance the teacher’s voice and have a very subdued level of reverberation or late-arriving echoes. It should also prevent the intrusion of unwanted sound from the building’s mechanical systems, adjacent spaces, and sources such as children, lawnmowers, roadways, trains, and airports [19
]. The presence of excessive noise or reverberation will lead to a greater percentage of missed words during classroom instruction. Poor acoustical conditions in the classroom impede the teaching–learning process and could lead to a progressive deficit in students’ academic performance. In addition to the cumulative negative impact of poor acoustics on pupil learning, excessive noise or reverberation can lead to supplementary stress and physiological harm for teachers.
Unhealthy and unsafe school conditions may also impair the quality of teaching and learning, which could lead to poor student attendance and performance rates, and in turn, reduce teacher and staff retention. A research study by [20
] has indicated that teachers have “higher asthma prevalence than other non-industrial worker groups”. According to [21
], the high asthma rates in teachers could be attributed to a school building’s reduced ability to maintain indoor relative humidity (RH), which increases allergens and irritants that are worsened by humidity. A survey of Chicago and Washington DC teachers by Schneider (2002) indicated that “30% of Chicago teachers and over 40% of teachers in Washington (DC) report[ed] that their rooms were uncomfortable”; this same study further identified a potential for increased teacher turnover due to undesirable indoor environmental conditions [21
Lastly, temperature and relative humidity can affect the indoor environmental quality of classrooms tremendously not only because they help determine the thermal comfort of the students, but also because they promote the growth of bacteria and mold, which can trigger allergic responses and become harmful in a classroom environment. Maintaining thermal conditions and air quality are important for HVAC in schools, yet efficient heating, ventilation, and air conditioning (HVAC) systems may be absent in some of these older school buildings. At present, most schools lack HVAC systems that respond to occupant behavioral patterns such as occupant density and their activities [21
]. The presence of these systems in schools would not only help improve occupant comfort, it can also reduce energy consumption.
Multiple case studies also show that older facilities without sustainable features or building upgrades have an impact on energy use due to their building attributes. The 2003 Commercial Building Energy Consumption Survey (CBECS) identified in Table B8
that over 60% of U.S. education facilities are 45 years old or older [22
]. High energy costs within these buildings may be exacerbated due to poor lighting and space heating, which when combined make the highest energy uses in buildings [23
]. However, facility managers are faced with shrinking budgets, which affects allocation of funds that could be used to update building systems and make sustainable upgrades. With rising energy costs and increasing building population, resources for renovations and building upgrades can be further limited.
Every year, K-12 schools spend over $
6 billion on energy, which is more than the US spends on textbooks and computers combined [25
]. As a result of the U.S. recession in December 2007, capital spending needed by States and Localities to renovate schools with modern systems and assemblies went down [26
]. Elementary and high schools (K-12) in the United States had their budget reduced by $
28 billion between the fiscal years of 2008 and 2013 [26
]. Hence, improving energy and water efficiency in urban schools can have a major impact on improving resource allocation in school maintenance and upgrades and can also potentially improve climate conditions in cities. These benefits are reflected in utility cost savings for the school district and in reduced power demands for the region, which decreases harmful airborne emissions.
To achieve optimal IEQ, energy improvement goals, and determine resource allocation in school facility management, school facilities need to evaluate their building conditions and determine occupant comfort and satisfaction in their environment through post occupancy evaluation (POE). POE is the process of systematically assessing a building and evaluating its energy, thermal, acoustic, visual, spatial, and ergonomic performances after it has been built and occupied [27
]. POE relies on the subjective surveys of IEQ variables, i.e., visual quality, air quality, thermal quality, acoustic quality [28
], and spatial quality, which impacts ergonomics. It also relies on objective IEQ measurements from the technical attributes of building systems (TABS) to determine how the systems impact the indoor environment and compare the results to subjective results of user satisfaction [28
]. POE is an invaluable tool to reveal the gaps between the design intent and the current state of building operations. An evaluation of a building’s systems and performance can serve as a springboard for effective retrofit and user-customized recommendations. POE can be used as a design aid through ‘feed-forward’ design charettes and support decision making for strategies and systems to implement in energy efficiency, occupancy comfort, and resource allocation. POE as a feedback tool can also be used in tandem with energy audits to support management of existing building systems by ensuring systems are working properly and as intended. In addition, personnel management can be improved as building performance has been linked to better performance through ergonomics and overall occupant health and wellbeing.
In practice, POE has been applied to numerous commercial and residential projects. The literature on commercial projects, especially for office spaces and educational facilities, is growing. Multiple research studies including [28
] have shown the multiple benefits of conducting POEs in office environments, which include energy efficiency and increased occupant productivity, comfort, and wellbeing. These studies used a combination of qualitative and quantitative methods, which consists of surveys and field measurements, to evaluate IEQ. The research study by [28
] further provided guidelines for conducting evaluations in office spaces regardless of building use or type, and these guidelines have been applied to many POEs of office buildings.
However, although there are numerous studies on the benefits of POE in schools [32
], they primarily focus on questionnaire-based methods. Furthermore, despite the growing number of post occupancy evaluations in schools, there is no consensus on how to conduct one to get data on all the important variables. The POE process has not been streamlined for easy replication by non-academic personnel. Many studies also focus primarily on teachers’ input; nevertheless, investigating the perceptions of students in their spaces increases the robustness of retrofit recommendation.
There has been growing interests for rigorous and detailed evaluation of learning spaces in research [35
], however this cannot be achieved by only evaluating teachers and staff contexts. A larger view of learning spaces should come from both the learning and teaching perspectives. Although teachers have great overviews of students’ IEQ conditions because they are the main points of contacts in school buildings, robust POE should include students’ perspectives. The studies by [38
] use integrated stakeholder POE frameworks to determine whole-school information and insights on sustainability management, occupant comfort, and occupant health and wellbeing. While they aimed for the same outcomes, both studies used different approaches. One research study [39
] used a method adapted from Photovoice to include students in the POE process in green schools, whereas [38
] adopted participatory action research (PAR) methods to determine the individual relationships of all types of occupants to their school buildings.
In addition to the differences in methods and approaches to conducting comprehensive POE in schools, school facilities also pose further complications. School building types vary, building ages can create uncertainties on building systems information, and natural environment conditions are constantly changing (including environmental pollution). Ultimately, the primary aim of this research was to develop a unified protocol for POE and measurements (+M) of critical indoor environmental quality variables in school facilities regardless of unknowns and building types.
POE+M combines user satisfaction questionnaires with physical measurements as well as ‘as-built’ records on the conditions of each building system. The evaluation process goes beyond the conventional performance measurements, and recognizes the interrelated nature of spatial, thermal, air, acoustics, and visual qualities, promoting occupants as sensors and controllers. This comes from the understanding of critical linkages between occupant satisfaction, environmental conditions, and the technical attributes of building systems to health, productivity, and life cycle costs.
A secondary aim of the research was to present the importance of all stakeholders in providing data that can be tailored to fit all their needs. Ideally, an IEQ team should include facility management and administrative staff, teachers, custodians, school nurses, school boards, contract service providers, parents, and students to ensure a broad range of valuable input is considered. The paper will illustrate the process for rigorous yet efficient data collection that will help school facilities make building maintenance and upgrade decisions. The protocol considers real-world circumstances of multiple objectives of stakeholders in decision making.
The POE methods described in this paper was informed by Park et al. [28
] guidelines for commercial office IEQ tests and field measurements using the National Environmental Assessment Toolkit (NEAT). This research recognized the differences between office buildings and school facilities and used the analysis of eight school facilities over an eight-year period to design a protocol more suited for schools.
Findings from POE+M of the eight schools have shown that school administrations are able to find complications they did not know existed. POE+M provides in depth investigation of IEQ variables and provides directions on modifications and improvements, which would otherwise be difficult. For example, the existence of IEQ and energy efficiency problems in school buildings can be inferred without measurements if certain conditions exist. Foul smells, glare, and loud equipment that distract occupants indicate that there are problems with air, light, and noise quality within a space, and those variables should be investigated. However, other indicators such as CO2 and air temperature may be difficult to ascertain. High levels of CO2 present in a room is difficult to determine because CO2 is odorless.
In addition, identifying the best temperature range in schools with K-12 students can be challenging as there is a wide variation in the age of students and a significant difference in metabolic rates. However, performing field measurements in many spots and at different locations will determine temperature variations in the space. This can guide optimal temperature ranges for classrooms per age groups. It is also difficult to determine the presence and location of air leakages in the building envelope without POE+M. Locating air leakages in the building envelope can lead to retrofit actions including upgrading window layers and roofing to improve air tightness.
Lighting has also remained a critical issue in the design of buildings for centuries, which is evident from the inclusion of daylighting in ancient architecture. Different configurations of illumination including daylight can be used to stimulate productivity and creativity among students in schools [49
]. Poor or inappropriate lighting can affect students’ health and performance as shown during the longitudinal studies. The robust observations, occupancy evaluation, and measurements helped provide in-depth insight to facility managers on IEQ problems.
Factors that contributed to effectiveness of the POE+M process in schools in the study included observations, workplan and field measurement manual, time mapping, and conversations with facility managers. Findings from conducting field measurements revealed that observations made at the beginning of the field measurements closely reflected data results. Observations are key to highlighting anomalies in data collection, supporting assessments at the early phase of field testing, and directing the selection of spot measurements. Locations for spot measurements can also be directed by observing air and thermal quality indicators such as the presence of dehumidifiers. Indicators of three IEQ variables can be easily observed; these variables include acoustics, thermal, and visual quality. For example, the presence of shading devices in a room can be determined by simple observation. This finding can direct the specificity of lighting and visual variables because the absence of shading devices indicates the presence of glare. This is also evident if there is no shading device, but there have been efforts made to block out the sun with makeshift items such as papers taped to windows.
Preliminary conclusions can also be made about the acoustics in the room by looking at the material choices for floor, ceiling, and wall surfaces, such as carpeting and tiling for the floors, and acoustical ceiling tiles (ACT) for the ceilings. Observations on school activities and background sounds can also support preliminary conclusions. In school E measurements in 2012, non-classrooms including corridors and other common areas displayed smaller deviation from the recommended NC limits of 35–40 (Figure 9
a) compared to that of the classrooms (Figure 9
Although the variance for the non-classrooms were lower, all the non-classroom spaces displayed much higher NC levels than recommended. This indicated that there was a pervasive issue with noise control in all spaces. The spaces with highest NC levels for non-classrooms were the gymnasium and second floor hallway. Two of the four walls in the gymnasium were external walls, which contributed to the background noises. Observations made prior to measurements highlighted that teachers were often found to be raising their voices to control the students, in some cases being very emotionally charged. This may be due to the high level of background noise as indicated in the field measurements, but also the inefficiency in the acoustical conditions to control student behavior.
Another important factor that pertains to increased POE+M efficiency is information. Collecting relevant, detailed, and extensive information on the building systems’ attributes and history will help fill gaps during analysis and clarify trends or explain preliminary results during field measurements. In addition, the combination of observation and the facility management interview would lead to optimum data collection.
Lastly, the POE process can also be effectively implemented when a workplan is prepared prior to the start of a field measurement. In a bid to stay closely within these optimum times, advance workflow preparation and even a mock field test are strongly advised. It is expected that errors may occur during the field measurements, such as recalibration of tools, thus advance preparation will help to keep the process brief. Having a team of at least four members also aids in time efficiency during the field tests. During the study, a four-person team mapped out their workflow allocating ten minutes to each measurement and planned to perform 10 measures in 110 min. The team spent an additional 25 min setting up the instruments at the various points of each location, and 10 more minutes on travel time.
Another factor that could cause time inefficiencies is instrument sharing. Some field team members noted that in measuring larger schools, waiting on instruments put them significantly behind their planned times and increased the duration of their measurement. Thus, for evaluation with larger teams, more instruments would be required for each team to successfully conduct their evaluation simultaneously. The instruments used with this study were part of the NEAT cart, however interested evaluators can use any tool with the same purpose (see Table 1
) for their school measurements. Furthermore, COPE and TABS shown in [28
] were also specifically used in this study, however evaluators can design their own occupant surveys and building attribute worksheets using the guidelines in the protocol.
The protocol for evaluating and measuring IEQ metrics within schools needs to be constantly updated, as guidelines and standards for IEQ keep changing based on new research. Areas of the protocol such as occupant satisfaction surveys and techniques for data collection need constant refining to increase clarity and efficiency in user adoption. Future work includes testing out the applicability of automated user satisfaction surveys in a school context in terms of the user friendliness, and the impact of automation on data collection and analysis. It also includes targeting more schools in urban, peri-urban, and rural locations to evaluate and measure in a bid to develop a more varied protocol.
Setting priorities for repairs and upgrades can often be complex. It is important for school management to maintain good communication and build consensus amongst priority stakeholders before utilizing school resources. Occupancy evaluation and site measurement data can help stakeholders’ decision-making on resource allocation.
The goal of this research was to develop and design a protocol to support POE+M of critical indoor environmental quality variables in school facilities. POE+M are important for facility managers and school administrations to identify which variables have direct or indirect impact on the occupants’ perceived satisfaction regarding the air, spatial, thermal, visual, and acoustic qualities; all of which are valuable in student learning. Important recommendations came from POE+M at these schools, many of which included consultations with mechanical and electrical experts. For example, improving IAQ recommendations included using source control, filtration, and ventilation to dilute contaminants.
There has not been a clear universal protocol for POE, especially in school facilities, but this paper provides a clearer picture on the process for data collection, analysis, and reporting of post occupancy IEQ metrics in schools. Results of post occupancy evaluation and measurements can help tackle the cost and budget challenges school administrations currently face and provide the many benefits of POE in design, management, and benchmarking of school buildings.
Through the study of these eight schools, it has been determined that post occupancy evaluation can be performed at schools using tools and techniques for data collection that can be easily replicated. The three-step protocol of pretest, testing, and post-test will help source valuable data from the field, support analysis, and provide reports that will serve as first steps towards building upgrades and facility management.